Some may say that it is a wavelength of light or representation of energy. Others, that it is a tool for creating and expressing yourself. There are endless ways to define and describe it, but one thing is for certain - as people, we have a remarkably intimate relationship with colour.

Colour Theory and Psychology

Understanding colours through an artistic and scientific lens grants us insight into how we perceive visual stimuli and how we can utilize some of its power to create in ways that engage the human psyche. One of the earliest forays into colour theory was Goethe’s Theory of Colours from over 200 years ago. He theorized about how colours have an impact on mood and emotion. For example, red-yellow was linked to feelings of warmth and gladness, while blue was associated with coldness and melancholy. Nowadays, leveraging colour to achieve a certain goal is a skill practiced everywhere from cinematography to logo design. The question of how colours came around to affect us in such a deep way has been a long debated issue. Let’s talk about a very primal colour: Red. One study noted that in some animals, primates included, the visibility of bright red oxygenated blood on bare skin was associated with aggression or arousal. War and conflict meant blood spilled, but that stems from how blood also symbolizes our life force. From the times we were hunter-gatherers, the colour red has been associated with fresh meat or ripe fruit; and now the colour is widely used in the food industry. It is the typical colour of sports cars because it is synonymous with power and aggression; but on the other hand, red crosses in medicine or red potions in video games indicate vitality and restoration of health. It can be made to represent many different feelings, but like the woman in the red dress from The Matrix, this colour is one that catches your eye.

Colours and Emotions

Other colours can be described similarly. Green is the colour of the chlorophyll in plant life, and is associated with things like nature, growth, and sustainability. Purple is often regarded as the colour of royalty and the elite, and was worn by the people in power from as far back as ancient Rome. The exclusivity came from the rarity of purple dyes back then, making them worth its weight in gold. The blue of the ocean or a clear sky became associated with calmness and vastness. The colour blue has also shown us how light and colour can have a more direct effect on our brain. Some studies suggest that prolonged exposure to short-wavelength blue light led to increased alertness and decreased fatigue. Blue seems to contradict itself - symbolizing calmness while making people more alert. There are many colours with both positive and negative associations and are heavily dependent on context. The stories of how these associations came about are likely a combination of many factors over thousands of years of human existence - spanning everything from our most primal instincts to social learning and culture.

Common colour emotion guide, Illustration by Reciprocal Space

Complementary Colours and Colour Harmony

Up to this point, we have only talked about colours individually; however we rarely experience colour in that way. Colours mix and mingle everywhere, and understanding how we feel colour combinations is just as important as understanding the colours themselves. This is where everyone's favorite colour theory tool comes in - the colour wheel. It helps us visualize colour combinations that look good, and there are various types of combinations that are staples of design. The most basic being complementary colours, which are the ones opposite each other on the wheel. Analogous colours on the other hands are ones right beside each other, like red paired with maroon and orange. Another type, known as triadic, takes three colours that are equally 120 degrees apart on the wheel. The feeling that some colours look better together than others seem to be a very innate part of us, like how musical notes arranged to form chords and harmonies just seem to work. This has much to do with how our brains receive and perceive light. Our eyes have photoreceptor cones that are responsible for giving us colour vision. There are three types of cones - one for short, medium, and long wavelengths of light. The shorter wavelengths are higher energy, like blue and purple. The middle wavelengths are around green, and the longer wavelengths are lower energy light like red and orange. How our brains process the information from those different cones are what allow us to perceive colour. Seeing complementary or triadic colours together means that your eyes are getting light from all across the different wavelengths, which stimulate the individual cones in a way that your brain perceives as balanced or pleasing. The way colour stimulates us is a unique reflection of who we are - a mix of human instinct, social learning, pop culture, and everything in between. Good use of colour means being able to use it to communicate and express feelings as if it were some unspoken language that we all can understand.

The colour wheel summary, Illustration by Reciprocal Space

Additional Sources:

Elliot, Andrew J. (2015). Color and psychological functioning: a review of theoretical and empirical work. Frontiers in Psychology.

Roy, S., Banerjee, A., Roy, C. et al. Brain response to color stimuli: an EEG study with nonlinear approach. Cognitive Neurodynamics volume 15, pages 1023–1053  (2021).

Steven W. Lockley, PhD, Erin E. Evans, et al. Short-Wavelength Sensitivity for the Direct Effects of Light on Alertness, Vigilance, and the Waking Electroencephalogram in Humans, Sleep, Volume 29, Issue 2, February 2006, Pages 161–168